Toy airplane



Sept. 29, 1936. G. BOEHME 2,055,620

TOY AIRPLANE Filed June 24, 1935 2 Sheets-Sheet 1 At/arny:

Sept. 29, 1936. G. BOEHME 2,055,626)

TOY AIRPLANE Filed June 24, 1935 2 Sheets-Sheet 2 jiwezziar."

GUS TA V BOEHME "m mawm A ffan-re Patented Sept. 29, 1936 UNITED STATES PATENT OFFICE Application June 24, 1935, Serial No. 28,203 In Germany February 23, 1933 16 Claims.

This invention relates to instructive toy airplanes, and has for its object to provide a flying toy airplane suited particularly for purposes of instruction by being equipped with means which prevent smashes during landing. The life of the improved airplane is therefore quite long, and as the plane is further capable of withstanding rough handling, the player is enabled to carry out a large number of flights under the most varied conditions and circumstances for his instruction.

The invention, above all, aims at protecting the hollow wings during landing, which for this purpose are connected with the fuselage so that they can elastically fold upwards and return to their position. On striking the ground during landing of the airplane, the wings immediately recede upwards, the shock being absorbed by cushioning,

and owing to this cushioning effect instantly return automatically to opereting position, so that the airplane is practically ready for service again directly after landing. If the wings are braces, the support struts, according to their arrangement on the underside or top of the wing, are elastically extensible or elastically bendable, and in the latter case the support strut consists preferably of curved steel band which in simplest manner combines stiifness and elasticity.

The invention further provides to render the rear part of the body carrying the tail unit elastically bendable so as to permit the tail unit to incline considerably towards the side and re-'- turn automatically in case of bumpy landings,

whereby the landing forces efiective at that point are also converted into cushioning action and smashes prevented. Furthermore, the forces stressing the wings are correspondingly reduced thereby.

A particularly advantageous construction results if the wing having a hollow profile can elastically bend transversely to the direction of flight, as the deflection will then take place directly at the striking points. An elastically bendable construction is attained by producing the longitudinal carrying elements of the wing structure, such as spars, nose and trailing edge stiffening strips, from transversely cambered steel band.

By way of example, the invention is illustrated in the accompanying drawings, in which Figure- 1 is a partial top view of the toy airplane; Fig. 2, a side view thereof with the front-wing removed; Figs. 3 to 8 are enlarged sections on the lines III-III, IV- IV, VV, VIVI, VII-VII, VIII-VIII, of Figs. 1 and 2; Fig. 9 is an enlarged section of the spar connection; Fig. 10, a top view of another form the rear part of the body; Fig. 11, a section on the line XI-XI, of Fig. 10; Figs. 12 and 13 show the use of difierently constructed support struts; Figs. 14 to 16 are views of an elastically bendable wing, Fig. 14 being a longitudinal section on the line XIV-XIV, of Fig. 15; Fig. 15 being a top view and Fig. 16 an enlarged section on r the line XVI-XVI, of Fig. 15.

Referring to the drawings, l2 are warping structures of hollow wings shown without covering and consisting each of a U-shaped light metal spar 4!, the U-shaped light metal ribs 38 arranged thereon and secured thereto by tubular rivets, a hollow front strip i8 andan angular metal trailing edge stiffening strip 41.. On each wing 30 designates asupport strut of cambered steel band disposed on the upper side of the wing. The strut 30 is secured with one against rotation to an angular member 85 which reinforces the point of intersection of the longitudinal spar 4| and a rib 38, and the other end thereof extends into a member 50 secured to the body ."5 and serving for adjusting the support struts and having a longitudinal slot 5| in which a screw 52 is adjustable and fixable. the stiffness of the struts the upper end of the band 30 is connected with the member 50 by means of a filling 88 to maintain the camber.

The fuselage l5 contains in an opening in its lower part a thick fitting and carrying rubber piece 9| which as a filler directly connects both wing spars 4| by being arranged in the depression of the spars and united therewith by the clamping plate 92 and the screw 93, as indicated in Fig. 9. The second point of attachment of each wing is located at its trailing edge whose stiffening strip 41 extends into a steel band 94 that canbe screwed to the body, as shown in Fig. 5. On each side of the body a projection 95 is further provided which forms a butt joint with the front edge l8 of the wing and serves for supporting it.

In case of oblique bumpy landings, the wing i2 touching the ground deviates upwardly owing to its jointlike connection to the body l5 by means of the elastic members 9|, 94 and its support by the bendable steel band strut 30, so that the landing shock is converted into cushioning action and does not cause destruction of the wing. After the effect of the shock has been overcome To increase the wing instantly returns automatically to its band, rigid strut members 53 may be used for instance on the upper side of the wing articulated to the body, which are interconnected by an elastic joint 54 and articulated to the-body and wing. Support struts of this kind also bend and automatically extend again. According to Fig. 13, on the underside of the wing connected 'to the body I5 by the joint 55 elastically extensible struts, such as the telescopic tubes 55 cushioned relative to one another, can be provided which are articulated to the body and wing and permit elastic upward deviation and automatic restoration of the latter.

The rear part of the body comprises two cambered steel bands 96 which face each other with their hollow sides, are connected in cambered fashion to the body 15 and the tail unit I3'by; say, the fillers 88 and spread at half of their length by an inserted distance piece 91. This spreading renders the steel bands 96 which are covered'with a yielding fabric 89 in streamline manner torsion proof.

In the construction according to Figs. and

11 the two cambered steel bands 96 are connected in spread position and cambered fashion to the end l5a of the body, so that aspecial spreading member can be dispensed with. The invention of the bendable rear part of the body is not limited to the embodiments shown, and the bands 96 mayalso be arranged horizontally and face one an-' other with their cambers.

The surfaces of the tail unit l3 consist of artificial resin material reinforced at the edge by the metal strips 98. Such surfaces are very light and resistant. When the airplane lands obliquely or on its nose, the tail unit, owing to the bending of the steel band body 96, elastically deviates tothe side and automatically returns into normal position after the deflection of the body is completed. j v

The parts -l5, l8, 4!, 41 may consist of suitable structural materials like metal, wood or artificial substances. For covering the wings canvas or other material can be used. The airplane can be thrown into the air by hand or by a catapult device engaging the hook 51 or driven by a compressed air motor, etc. and propeller. By displacing the point 52in the longitudinal slot 5| the wings are twisted or warped, whereby they are setdifferently, so that the training flights can be made highly interesting.

.In the construction according to Figs. 14 to 16 the wing I 2a is connected to the body l5 by ascrew 58 so as to be easily detachable.- The ribs 38a are pressed from light metal or consist of some other strong material. The longitudinal carriers firmly connected with the ribs and form:- ing part of the wing structure, such as the principal spar a, the nose strip I81: and the trailing edge stifiening strip Ha, are formed from a cambered steel band whose concave curvature faces the ribs 380. and is accurately adapted to the rib profile at the points of connection. The steel bands 4 la are the flanges of the main spar whose web is formed by the ribs 38a. The steel bands are connected by means of solid or tubular rivets 45 on the outside of the rib flanges 39a. The nose.

strip i811 and the trailing edge stifiening strip l9a are provided singly and only on one side of the ribs, which makes it possible for them to deflect to the same'extent as the main spar whose widely spaced flanges touch one another during bending of the wing. 99 are bracings of wire, threads, etc.

the rib. The wing tip I0! may consist of light metal and is preferably connected only to the lower one of the steel bands forming the main spar. 30a designates the support strut of cambered steel band arranged on the upper side of the tip alone or bring about the bending of the sup port strut.

The wing according to the invention may, in

-by means of the members 5la, 52a the wing can be warped and set differently.

I claim:-

1. An airworthy toy airplane, comprising a body, hollow wings connected with the body in jointlike manner. and struts of cambered steel band between the wings and body disposed on top, the said steel bands being adapted to maintain the wings in their normal operating position during normal flight, but yielding to shocks coming from the underside of the wings, such as those resulting from oblique landings, to cause them to fold-upwards and to return automatically into their original operating position when the stresses are removed.

2. An airworthy instructive toy airplane, comprising a body and hollow wings with struts to .stifiening strip, said spars being interconnected by a flexible member and the trailing edge stiffening strips being connected with the body by steel band.

4. -A toy airplane, comprising a body, a tail unit on the rear part of the body and hollow wings, elastic connecting means between the body and wings for rendering the wings elastically foldable' in upward direction and returnable to their normal position, the rear part of the body carrying the tail unit being elastically bendable, the rear part of the body carrying the tail unit being formed of spread cambered steel bands coming together in front and rear and the steel bands being provided at at least one point of their free length with a firmly inserted distance piece for spreading them.

5. A toy airplane, comprising a body, a tail unit on the rear part of the body and hollow wings, elastic connecting means between the body and wings for rendering the wings elastically foldable in upward direction and returnable to their normal position, the rear part of the body carrying the tail unit being elastically bendable,

the rear part of the bod; carrying the tail unit consisting of cambered steel bands connected .with a broad end of the body and converging.

towards the tail unit.

6. An airworthy instructive toy airplane, comprising a body, a tail unit and hollowwarping wings, said wings being connected with the body in jointlike manner and strutted relative to the body by cambered steel bands, thepoints of connection of the cambered steel band struts and body being adjustable and fixable in" flying direction, the rear part of the body carrying the tail unit being elastically bendable.

7. A toy airplane, comprising hollow wings with a covering of soft material and an internal carrying structure, said structure having elastically yielding longitudinal carriers and ribs connected therewith. at least some of these longitudinal carriers consisting oi cambered steel band for rendering the wings elastically bendable and automatically returnable to their extended position.

8. A toy airplane, comprising a hollow wing with a covering of soft material, a carrying structure inside the wing consisting of at least one,

longitudinal spar and cross ribs connected therewith, said longitudinal spar having flanges of cambered steel band and being. elastically bendable.

9. A toy airplane with hollow wing, said wing having an internally disposed structure comprising at least one longitudinal spar, a nose strip and a trailing edge stiifening strip. the flanges of said spar. and the nose and stiilening strips consisting of cambered steel band.

10. A toy airplane with hollow wing, saidwi'ng comprising an inner structure and a covering of soft material, the structure consisting of ribs and longitudinal carriers connected therewith, said carriers being made of cambered steel band and with their concave side disposed on the outside of the ribs.

11. A toy airplane, comprising a body, hollow wings and a strut arranged between the body and wings above the latter, the wings having an inner structure of ribs, longitudinal carriers connected with said ribs and a covering of flexible material, said longitudinal carriers and strut consisting of cambered steel band.

1 2. An airworthy toy airplane, comprising a body and hollow wings, the wings being jointlike connected with the body-and braced against the latter by struts disposed on top. the said bracing struts resisting compressive stress re-. :sulting under flying conditions and made elastically flexible, said iointlike connection and elastic flexibility being adapted to permit the wings toswing upwards when encountering landing shocks or stresses from the under side 01' the body and hollow wings, the wings being jointlike connected with the body and braced against the latter by struts disposed on the under side of the wings, the said bracing struts resisting tensile forces resulting under flying conditionand made elastically extensible, said jointlike connection and elastic extensibility being adapted to permit the wings to swing upwards when encountering landing. shocks or stresses from the under side of the wing and to restore them automatically into their normal operating position when the-stresses are removed.

15. An airworthy airplane, comprising a body, hollow wings with spaced upper and under surfaces, a bracing structure in said wings, the structures being jointlike connected with the body, elastic means adapted to co-operate with the iointlike connection and to maintain the wings in their normal operating position during normal flight, said iointlike connection and elastic means being adapted to permit the wings to assume limited upward yielding movements when encountering landing shocks or stresses from the under side'of the wing and to restore them automatically into their normal operating position the one hand, to maintain the wings and tail unit in their normal operating position with respect to the body during starting and flight and on the other hand cause them to assume limited yielding movements when encountering landing shocks and to restore them automatically into their normal operating position when the stresses are removed.

' ons'rav noamm. 

